Within both countries, the most frequent example of lying was parents threatening to leave their children alone in public unless they behaved, the BBC reported.

Other forms of persuasion are more fantasy-based, like the classic Pinocchio tale that if you lie to someone, your nose will grow longer — or that your Fairy Godmother is watching everything you do.

The study’s authors, from the University of California, San Diego in the U.S., Zhejian Normal University in China and the University of Toronto in Canada, focused on what psychologists refer to as “instrumental lying” — defined here as “lying to influence the behavior of others.” The study was based on interviews with about 200 families.

The lie most commonly used – popular with both families in the U.S. and China – was parents pretending to leave a child alone who refuses to follow a parent, according to the study.

“The pervasiveness of this lie may relate to the universality of the challenge parents face in trying to leave a place against their child’s wishes,” the researchers said.

Another popular lie the study’s authors found among parents in both countries was “a false promise to buy a requested toy at time indefinite time in the future.”

The researchers established different categories of untruths, which included:“Untrue statements related to misbehavior”; “untrue statements related to eating”; and “untrue statements related to spending money.”

Some of the lies recorded were startling; for instance, under “untrue statements related to leaving or staying,” one parent was recorded as saying: “If you don’t follow me, a kidnapper will come to kidnap you while I’m gone,” according to BBC News.

The researchers found that instrumental lying was more common among parents in China than in the U.S., especially lies related to eating and misbehavior.

“The study found there was an acceptance of such lies among parents when they were used as a way of reinforcing desirable social behavior,” reported the BBC.

Parental lying is important, the researchers wrote, because “this practice may play a role in children’s lying behavior and evaluations of others who lie, two issues that are widely recognized as central to moral development.” In conclusion, they wrote, their study raises “important moral questions for parents about when, if ever, parental lying is justified.”